1. Technical Field
This invention relates to exhaust systems and, more particularly, to a dual mode vehicle exhaust system for allowing a user to generate a desired audible sound from an existing muffler exhaust system of the vehicle.
2. Prior Art
There was a time when America's auto makers competed to offer consumers the biggest tail fins, the most powerful engines, the latest in bucket seats and vinyl roofs. Many car models, referred to as muscle cars, produced a distinctive engine sound that conveyed a sense of power waiting to be unleashed. Today, however, emphasis is placed on producing fuel efficient, quieter cars that make very little engine noise. Many motorists, however, especially car aficionados, regardless of what kind of car they buy, want a car that communicates a distinguishing sound of controlled power, like a finely-tuned instrument. Obviously, it would be advantageous to provide a means for allowing motorists to select an exhaust pipe that produces a quiet, muffled sound or a distinctive and powerful sound.
U.S. Pat. No. 4,342,194 to Paddock discloses an electric air control switching valve for use in controlling the delivery of secondary air from an engine driven air pump selectively. The valve functions with both engine operation and the operation of its associated emission control system, with either the exhaust manifold of an engine, preferably at a location closely adjacent to the exhaust ports of the engine. The valve further functions during low temperature engine operation, to the atmosphere, as at the dirty side of the air cleaner associated with the induction system of the engine. During low temperature engine deceleration, to a converter in the exhaust system for the engine downstream of the exhaust manifold during normal engine operation, or again to the atmosphere, as at the dirty side of the air cleaner, when the converter temperature exceeds a predetermined temperature. Unfortunately, this prior art example does not enable a user to determine what type of sound is emitted from a vehicle exhaust system.
U.S. Pat. No. 5,388,408 to Lawrence discloses an exhaust system for vehicles and other devices with internal combustion engines such as boats, airplanes, lawnmowers, tractors, and the like. The system includes a sound attenuating chamber with a single, common opening in an imperforate container providing access for exhaust gases both to and from the container while attenuating the exhaust sound thereof. The system maintains low back pressure during operation. Resonator tubes and optional sound absorbing material may be used in the chamber to control exhaust sounds. An optional, remote-operated, sound control valve upstream of the chamber allows individualized control of the exhaust sound by the vehicle driver. An optional baffle in the exhaust outlet and/or an optional helical insert in the exhaust pipe further deadens the sound. In a preferred form, the system is attached downstream of a catalytic converter and includes dual sound attenuating chambers and dual exhaust outlets at the opposite vehicle sides between the front and rear wheels. Unfortunately, this prior art example does not enable a user to determine what type of sound is emitted from a vehicle exhaust system.
U.S. Pat. No. 6,202,409 to Taylor discloses an acoustical system with a sound-producing transducer mounted in the exhaust pipe of the engine, at proximity of the exhaust port and oriented toward the exhaust port, for emitting and directing a sound pulse toward the exhaust port. The sound-producing transducer is operable for bouncing a first sound pulse off the piston wall during the expansion cycle and immediately before opening the exhaust port, for creating a low pressure zone at the exhaust port and for enhancing the evacuation of exhaust gases from the combustion chamber. A second sound pulse is emitted at every compression cycle of the engine and directed at the exhaust port immediately before closing the exhaust port. The combination of the first and second sound pulses at every rotation of the engine provides an efficient scavenging and plugging of the engine for increasing the performance of the engine. Unfortunately, this prior art example does not enable a user to determine what type of sound is emitted from a vehicle exhaust system.
Accordingly, the present invention is disclosed in order to overcome the above noted shortcomings. The present invention satisfies such a need by providing a system that is convenient and easy to use, lightweight yet durable in design, and designed for allowing a user to generate a desired audible sound from an existing muffler exhaust system of the vehicle. The system is rust resistant, heat resistant, and allows a user to adapt a vehicle exhaust system to allow motorists to select the type of exhaust sound produced by a vehicle. The pipe that produces a relative quiet sound is advantageously used in restricted noise areas or residential areas and the loud exhaust pipe is used when the driver wants to produce a powerful resonating sound that sounds like a muscle car or an expensive sports car. The pipe selected and type of noise produced is determined by the switch position selected by the driver. The present invention is simple to use, inexpensive, and designed for many years of repeated use.